Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Searching Sound Valves M40 Monoblocks schematic
Searching Sound Valves M40 Monoblocks schematic
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 15th November 2006, 07:11 AM   #1
echo_airiti is offline echo_airiti  Taiwan
diyAudio Member
Join Date: Nov 2006
Post Searching Sound Valves M40 Monoblocks schematic

I own a pair of used Sound Valves M40 Monoblocks, I am trying to make some modification on it, Please help me to get the schematic of the amplifier, Your helps are greatly appreciated. Many many thanks!

My email address: echo@airiti.com
  Reply With Quote
Old 15th November 2006, 04:23 PM   #2
kevinkr is offline kevinkr  United States
diyAudio Moderator
kevinkr's Avatar
Join Date: Sep 2004
Location: Boston, Massachusetts
Searching Sound Valves M40 Monoblocks schematic
I googled Sound Valves and Sound Values (the name of the original company.) I reviewed their VTP-101i pre-amp more than 10 years ago..

Unfortunately they seem to be out of business at this point. I found their old web address and unfortunately it now belongs to a cyber squatter.. www.soundvalves.com

The M40 is very similar to the Dynaco MKIV IIRC, but doesn't use a 7199 but something like a 6AN8 instead? (Again IIRC)

I have seen and heard the M40, but my recollection is more than a little fuzzy since it was more than 10yrs ago.

Try triode connecting the EL34 output tubes, remove the UL taps coming from the output transformers from pin 4 of the EL34's and connect a 220 - 1K resistor from pin 3 to 4. (screen grid to plate) Be sure to insulate the disconnected tap wires well as there is full B+ plus rather a lot of AC audio voltage present when operating.

Upgrade the coupling caps as there are much better ones out there now.

Here is a link to a review of the pre-amplifier (not my review) with possibly useful historical contact info (ignore the email and website addresses obviously):


Sorry, wish I could be of more help.
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 25th January 2008, 01:32 AM   #3
skypilot_one is offline skypilot_one  United States
diyAudio Member
Join Date: Dec 2007
These sound best stock. They did a good job on the circuit and they did not approve of wiring for triode. I do have the original schematic if you still need it.
  Reply With Quote


Searching Sound Valves M40 Monoblocks schematicHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sound Valves M40 schematic 11ongas Tubes / Valves 8 16th March 2018 03:52 AM
Hafler parts - Sound Valves? DMF Solid State 24 30th November 2016 05:15 AM
Please Help with Sound Valves M40 Monoblock Bias Adjustment Procedure!!! mq1688 Tubes / Valves 2 6th April 2013 05:14 AM
Searching schematic for Bogen sound system LOL tube preamp Lily Instruments and Amps 3 10th January 2007 09:38 PM
Sound Valves M-40 assistance audioquestM-40 Tubes / Valves 3 20th December 2005 05:46 PM

New To Site? Need Help?

All times are GMT. The time now is 10:01 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio